论文部分内容阅读
提出了考虑颗粒摩擦系数空间变异性的砂土双轴剪切响应分析方法。采用随机场模型表征颗粒摩擦系数空间变异性,通过Karhunen-Loève展开方法离散接触摩擦系数随机场,编写了基于颗粒流程序PFC2D和MATLAB的随机模拟耦合分析程序。研究了摩擦系数空间变异性对密砂试样的双轴剪切响应影响规律。结果表明:1)提出方法可有效地考虑颗粒间接触摩擦系数变异性对土体材料双轴压缩宏观力学行为影响;2)密砂试样在剪切过程中的应力-应变关系曲线、体积-应变关系曲线的变化规律与颗粒间接触摩擦系数不确定性密切相关,在初始加载阶段随机模拟的偏应力曲线、体积应变曲线基本重合,继续加载后曲线开始发散;3)垂直相关距离对峰值偏应力均值与标准差影响明显大于水平相关距离。颗粒接触摩擦系数的均值对峰值偏应力的影响大于摩擦系数空间分布的影响。摩擦系数的空间分布会影响剪切带的形成位置。
The biaxial shear response analysis method of sand considering the spatial variability of particle friction coefficient is proposed. The random field model was used to characterize the spatial variability of the particle friction coefficient. The random field of contact friction coefficient was discretized by Karhunen-Loève expansion method. A stochastic simulation coupling analysis program based on particle flow program PFC2D and MATLAB was designed. The influence of spatial variability of friction coefficient on biaxial shear response of sand samples was studied. The results show that: 1) The proposed method can effectively consider the influence of the variability of contact friction coefficient between particles on the macroscopic mechanical behavior of biaxial compression of soils; 2) the stress-strain curve, The variation law of the strain curve is closely related to the uncertainty of the contact friction coefficient between particles. The deviatoric stress curves and the volume strain curves of the random simulation are basically coincident during the initial loading stage, and the curve begins to diverge after the continuous loading. 3) The influence of stress mean and standard deviation is obviously greater than the horizontal correlation distance. The influence of the average particle contact friction coefficient on the peak deviatoric stress is greater than that of the friction coefficient. The spatial distribution of friction coefficient will affect the formation of shear band.